Wellbore drilled and equipped for in-well rigless intervention esp

ABSTRACT

A string for drilling a well for installation and retrieval of ESP equipment without a rig. A well is drilled past the end of casing which has been cemented in place and extends to a wellhead at the surface. A receptacle is attached between production casing joints and run into the well  10 . The receptacle is a tubular member with an inclined pocket formed on a side. At least one passage or port in the pocket intersects with a passage in receptacle with one or more lengths of tubing attached to the pocket. A wet connector within the production casing is landed in the receptacle and self aligns to the tubing. Electrical wires run within the tubing mate and lock with the wet connector. This allows an ESP to be run into the well via winch such that it stabs into the wet connector to receive power.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to provisional application 61/225,292 filed Jul. 14, 2009.

FIELD OF THE INVENTION

This invention relates in general to installation and retrieval of electrical submersible pumps (ESPs), and in particular to a string for drilling a well for installation and retrieval of ESP equipment without a rig.

BACKGROUND OF THE INVENTION

ESP's are used in wells to pump formation fluids, such as oil, up to the surface via production tubing. Generally a rig is required to install and retrieve an ESP and its components, such as a wet connector or electrical cables, down and out of the well. Once in place the ESP system controls the production of fluid to the surface.

It is desirable to install and remove the ESP and its components in a cost-effective, simplified, and environmentally friendly manner. However, the rig is a critical and expensive resource in subsea or remote applications. In addition, providing power and connection for the ESP's motor can be difficult.

A technique is thus needed to install and retrieve and ESP and its components that is feasible and cost-effective.

SUMMARY OF THE INVENTION

In an embodiment of the present invention, a wellbore drilled and equipped for in-well rigless intervention is illustrated in which an ESP string can be installed or retrieved without the use of a rig. The wellbore is drilled past the end of casing cemented in place and a receptacle is attached between production casing joints and run into the well. The casing extends to a wellhead at the surface. The receptacle is a cylindrical tubular member with an inner diameter that may be the same as that of the casing. An inclined pocket may be formed on a side of the receptacle.

A passage or port in the pocket intersects with the passage in receptacle, which is located below the lower end of casing in an embodiment of the present invention. Thus, the receptacle communicates the tubing to the interior of the production casing. One or more lengths of auxiliary tubing is attached to the pocket and run into the well at the same time the casing is being run, with the auxiliary tubing strapped or clamped to the exterior of the production casing. Auxiliary tubing is much smaller in diameter than casing and can be either continuous coiled tubing or sections of tubing screwed together. The receptacle, casing, and auxiliary tubing are cemented in place within the well in a conventional way.

With the receptacle and auxiliary tubing in place within the well, a wet connector is run inside the production casing and landed in the receptacle, self aligning with the coiled tubing. Electrical cables can then be run down the inside of the coiled tubing and connected to the wet connector. In this embodiment, three electrical cables for 3-phase power are individually run down three individual coiled tubes. In this embodiment, the wet connector has three conductors located on its inside surface located above the passages in the receptacle to allow the conductors to electrically communicate with the ends of the electrical cables. The conductors may connect to the stab-in section of the wet connector via electrical connections. The auxiliary tubing connected to the receptacle and housing the electrical cables, makes it possible for the electrical cables and wet connector to be installed or retrieved without a rig. This is because the electrical cables are not clamped to the side of tubing string as in conventional methods.

Once the wet mate connector and electrical cables are in place, the wellbore is then ready to receive an ESP assembly that can be run into the well via a wireline winch, for example. The ESP assembly may include a motor, a seal section, and a pump in this embodiment. The motor in this embodiment is located at the bottom of the ESP assembly and has a conductor stab extending from below. The ESP is lowered into the well until the stab-in section of the wet connector engages the conductor stab below motor. The conductor stab can have three conductor pins that stab into receptacles located in the stab-in section through the use of an orientation device on the conductor stab that orients the pins with the receptacles. The receptacles allow electrical communication with the power cables to thus provide electrical power to the ESP. The ESP is electrically supplied by the electrical power cables connecting to the wet connector via the coiled tubing. Once the ESP is stabbed into place, a packer is set to seal the discharge of the ESP from its intake and the receptacle. If the ESP must be retrieved, the ESP assembly may simply be retrieved by wireline winch as well.

The invention is simple and allows for cost-effective ESP installation and retrieval via a wireline or coiled tubing. This invention advantageously allows the ESP assembly, wet connector, or electrical cables, to be installed or retrieved within a wellbore drilled to accommodate rigless in-well intervention. This invention could help operators decrease the overall cost of installation and retrieval of ESP systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a well production assembly during installation of the production casing, in accordance with the invention.

FIG. 1A is a sectional view of the production assembly of FIG. 1 taken along the line 1A-1A of FIG. 1.

FIG. 2 shows the assembly of FIG. 1 during cementing of the production tubing and coiled tubing, in accordance with the invention.

FIG. 3 shows the assembly of FIG. 2 with a wet connector run inside the production casing and landed in the receptacle, in accordance with the invention.

FIG. 3A is a sectional view illustrating portions of the production assembly of FIG. 3 taken along the line 3A-3A of FIG. 3.

FIG. 4 shows the assembly of FIG. 3 with a wire line run into the coiled tubing, in accordance with the invention.

FIG. 5 shows the assembly of FIG. 4 with an ESP run inside the production tubing and connected to the wet connector, in accordance with the invention.

FIG. 5A shows an example of how the conductor stab connects to the stab-in portion of the wet connector, in accordance with the invention.

FIG. 6 is a sectional view similar to FIG. 1A, but showing an additional embodiment using a single coiled tubing string, in accordance with the invention.

FIG. 7 shows an additional embodiment of a production assembly, with liner string run and cemented to the depth where the ESP is located, in accordance with the invention.

FIG. 8 shows an additional embodiment of a production assembly illustrating a liner string prior to installing a receptacle and coiled tubing, in accordance with the invention.

FIG. 9 shows the completed installation of the assembly of FIG. 8.

FIG. 10 shows an additional embodiment of a production assembly that uses a downhole safety valve, or similar valve, with the ESP system and also show the use of an additional coiled tube for a hydraulic line, in accordance with the invention.

FIG. 11 is a sectional view illustrating portions of the production assembly of FIG. 10.

FIGS. 12 and 13 show sectional views of additional embodiments with alternative coiled tubing configurations in accordance with the invention.

FIG. 14 shows an additional embodiment of a production assembly with two receptacles and a coiled tubing string for circulating the well, in accordance with the invention.

FIG. 15 is a sectional view showing the tubing string for circulating the well bypassing the first receptacle to connect to the bottom receptacle of FIG. 14.

FIG. 15A is a sectional view showing the tubing string for circulating the well connecting to the bottom receptacle of FIG. 14.

FIG. 16 shows an additional embodiment of a production assembly with the receptacle and coiled tubing attached to the production tubing, in accordance with the invention.

FIG. 17 shows an example of how the receptacle pocket receives an end cable assembly, in accordance with the invention.

FIG. 18 shows an example of an end cable assembly for a cable for latching onto a conductor in the receptacle pocket, in accordance with the invention.

FIG. 19 shows an example of the end cable assembly of FIG. 18 latched onto an electrical connection in the pocket shown in FIG. 17, in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, a well 10 is drilled past the end of casing 12, which has been cemented in place. A receptacle 14 is attached between production casing 16 joints and run into the well 10. Casing 16 extends to a wellhead at the surface. The receptacle 14 is a cylindrical tubular member with an inner diameter that may be the same as that of the casing 12 with a pocket 15 formed on a side and inclined. However, it is not required that the inner diameter of the receptacle 14 be the same as the inner diameter of the casing 12. At least one passage or port in pocket 15 intersects with passage in receptacle 14. Receptacle 14 is located below the lower end of casing 12. The inner diameter of the receptacle 14 can vary depending on the size of the casing 12. Preferably one or more lengths of auxiliary tubing 20 is attached to pocket 15 when the receptacle 14 is at the surface. In this embodiment, the receptacle 14, auxiliary tubing 20, and casing 16 run into the well 10 at the same time as part of the same string. The auxiliary tubing 20 can be strapped or clamped to the exterior of the production casing 16. Auxiliary tubing 20 could either be continuous coiled tubing or it could be sections of tubing screwed together. Auxiliary tubing 20 is much smaller in diameter than casing 16 and may be attached to the pocket 15 as a compression fit, or alternatively may be threaded or welded to the pocket 15. Alternatively, as shown in FIG. 3A, a plurality of pockets 15 can be formed on the receptacle 14, with each receiving auxiliary tubing 20.

The receptacle 14 communicates the coiled tubing 20 to the interior of the production casing 16. An isolation sleeve 18 can be placed on the top portion of the receptacle 14 during cementing to allow tools to operate below the receptacle 14 or to allow production of the well 10 without communication with the coiled tubing 20. The use of an isolation sleeve 18 is optional. Alternatively, a retrievable plug (not shown) can be located at the end of the coiled tubing 20 connecting to the receptacle 14. As seen in FIG. 1A, more than one auxiliary tubing strings 20 may be mounted to receptacle 14.

The assembly in FIG. 1 is then cemented in place in a conventional manner. Cement 21 (FIG. 2) flows around receptacle 14 and a lower portion of auxiliary tubing 14. Once the production casing 16 and the coiled tubing 20 is cemented in place as shown in FIG. 2, isolation sleeve 18 is removed. Then a wet connector 22 (FIG. 3) is run inside the production casing 16 via wireline or tubing and landed in the receptacle 14, self aligning with the coiled tubing 20. If the well is going to produce naturally, or by other means, the isolation sleeve 18 can remain installed. The wet connector 22 may be a standard wet connector. Alternatively, a wet mate connector such as that disclosed in pending application Ser. No. 12/060,525, which is herein incorporated by reference in its entirety, may be used.

Electrical cables 24 can then be run down the inside of the coiled tubing 20 as shown in FIG. 4 until the cables 24 mate and lock with the wet connector 22. A retaining ring or quick disconnect type connectors, for example, can be located at the passages of the receptacle 14 to lock the cables 24 in place. In this embodiment, three electrical cables 24, one for each phase, are individually run down three individual coiled tubes 20. This configuration of electrical cables 24 (FIG. 4) allows for the use of smaller diameter coiled tubing 20. The wet connector 22, in this example, also serves to isolate the coiled tubing 20 from the production casing 16. In this embodiment, the wet connector 22 has three conductors 17 located on its inside surface, as shown in FIG. 3A, that are located above the passages in the receptacle 14 to allow the conductors to electrically communicate with the end of the electrical cables 24. The conductors 17 may connect to the stab-in section 11 of the wet connector 22 via electrical connections 13. Alternatively, the conductors 17 could extend up to the stab-in section without the use of electrical connections.

FIGS. 17-19 show an example of a latching system for mating and locking a cable 24 within the receptacle 14 to electrically communicate with the wet connector 22 via a conductor 17. An end assembly 60 on the electrical cable 24 has a female electrical connection 61 that mates with a male electrical connection 62 located inside the receptacle pocket 15 and in communication with the conductor 17, as shown in FIG. 19. The electrical cable 24 and conductor 17 may be insulated. A diameter reduction 64 within the pocket 15 corresponds to circumferential recess 66 on the exterior of the electrical cable 24. The cable 24 is initially spooled into the auxiliary tubing 20 but eventually the weight of the cables 24 is sufficient to run it into the auxiliary tubing 20 and cause the circumferential recess 66 on the cable 24 to latch onto the diameter reduction 64 inside the pocket, locking the cable 24 in place while establishing electrical connection between the cable 24 and the conductor 17 within the receptacle 14. Together, the recess 66 and diameter reduction 64 form a latching system for the cable 24. A seal or O-ring 68 is located at a point on the electrical cable above the recess 66 to mechanically and electrically seal the connection between the female and male electrical connections 61, 62. To retrieve the cable 24, sufficient tension to overcome the latching system and weight of the cable 24 is placed on the cables 24 that will allow the recess 66 to unlatch from the diameter reduction 64, allowing the mating end 61 to disconnect from the male connection 62.

A wireline winch (not shown) can then be used to run an ESP assembly 26 into the production casing 16 using a wireline (not shown) that would normally not have an electrical conductor. ESP 26 comprises a motor 23, a seal section 25, and a pump 27. The seal section 27 equalizes lubricant pressure in the motor 23 with hydrostatic pressure on the exterior. A conductor stab 29 extends below motor 23. Pump 27 could be a centrifugal pump or progressing cavity pump. The ESP 26 is lowered into the well 10 until the stab-in section 11 of the wet connector 22 engages the conductor stab 29 below motor 23 at the bottom of the ESP 26 as shown in FIG. 5. The conductor stab 29 can have, for example, three conductor pins as shown in FIG. 5A that stab into receptacles located in the stab-in section 11. In this embodiment, an orientation device comprising raised surfaces 31 on the conductor stab to orient the pins with the receptacles. The receptacles can be connected to the conductors 17 with electrical connections 13 to allow electrical communication with the power cables 24. The ESP 26 is thereby electrically supplied by the electrical power cables 24 connecting to the wet connector 22 via the coiled tubing 20. The wet connector 22 has three electrical conductor rings that engage contacts that are free to move some in and out. Packer 28 is set to seal the discharge of the ESP 26 from its intake and the receptacle 14 and wet connector 22 have bores that allow production fluid to flow through them. ESP 26 discharges well fluid into production casing 16, which flows to the wellhead at the surface.

In another embodiment, as shown in FIG. 6, a single length of coiled tubing 30 can be run alongside the production casing 16. The coiled tubing or tubing 30 is sufficiently large in diameter to carry a 3-phase cable within. The wet connector 22 would have all three contacts aligned with the single port in the receptacle.

In a further embodiment, as shown in FIG. 7, casing 12 is installed and cemented in the well 10. The casing 12 is sufficiently large to accommodate production casing 34 and coiled tubing 20 to carry the electrical cables 24. A lower section having a smaller diameter than the casing 12 is drilled below the receptacle 14. The lower section is not large enough in diameter for receptacle 14. A string of casing 32 is connected to a lower portion of the receptacle 14 and lowered into the lower section. Receptacle 14 in this embodiment is above the lower end of the casing 12. An upper string of casing 34 that is the same diameter as casing 32 extends to a wellhead at the surface. Casing 32 is then cemented in place. A packer 36 below receptacle 14 is provided that prevents the receptacle 14, production casing 34, and coiled tubing 20, from being cemented in place. Packer 36 seals annulus between casing 32 and casing 12. Once the liner 32 is cemented, the wet connector 22 and ESP 26 can be lowered into the production casing 34 in the same manner as in the first embodiment.

In an additional embodiment, casing 12 is installed in the well 10. A lower section having a smaller diameter than the casing 12 is drilled and a liner 33 is hung from a liner hanger 38 and packer 36, as shown in FIG. 8. Liner 33 comprises joints of casing but the upper end extends only a short distance above the lower end of casing 12. The liner hanger 38 and liner packer 36 are installed just above the lower end of the casing 12 and cemented in place. Packer 40 is then set in upper end of liner. An assembly 41 will then be lowered into the well as part of a production tubing string 42, as shown in FIG. 9. Tubing string 42 extends to wellhead at the surface. The assembly comprises a receptacle 14 and wet connector 22 that are connected to the lower end of the production tubing 42. The assembly 41 further comprises, a tubular seal stab that stabs into lower packer 40 and joins the receptacle 14 to lower packer 40. Lower packer 40 could be run and set before installing receptacle 14 and tubing 42. After assembly 41 is installed, ESP 26, along with an upper packer 28, is lowered through the production tubing 42 and landed in receptacle 14. Coiled tubing 20 housing electrical cables 24 also comprises a part of the assembly 41 and connects to the receptacle 14 to allow the electrical cables 24 to mate and lock with the wet connector. The upper packer 28 is set against the inside of the production tubing string 42 to seal the discharge of the ESP 26. Upper packer 28 has a line leading to one of the ports in the receptacle 14. The line supplies energy to set the packer 28 and can be hydraulic or electric. When the assembly 41 is run down into the well 10 with the production tubing string 42, the lower packer 38 will have been previously set in the interior of the liner 32 to ready the well 10 for production.

In another embodiment, a downhole safety valve (“DHSV”) 44 or similar valve is added to an assembly 43 that is similar to assembly 41 in the previous embodiment, as shown in FIG. 10. A DHSV is a valve that is open only if hydraulic fluid pressure is being supplied. The assembly 43 comprises an upper packer 28, the ESP 26, coiled tubing 20, a receptacle 14, and a wet connector 22. The assembly 43 further comprises a lower packer 40 off of which the DHSV 44 will be hung before the production tubing string 42 is run into the well 10. The DHSV 44 can be used to control production from the well 10. To control the DHSV 44, an additional control line coiled tube 46 is provided through which a control line 47, normally hydraulic, can be run down to the receptacle 14, as shown in FIG. 11. The control line 47 will stab into the wet connector 22 to communicate with the DHSV 44. Alternatively, hydraulic fluid could be pumped directly into the tube 46 to control the DHSV 44 instead of through a separate control line. In this embodiment, the wet connector 22 is the interface for both the power cables 24 serving the ESP 26 and the control line 47 that controls the DHSV 44. Alternatively, an additional length of coiled tubing 48 can extend from receptacle 14 along with the electrical coiled tubing 20 and the control line coiled tubing 46. The additional coiled tubing 48 can be used to circulate brine around the ESP 26 to clean it or to clean the well 10 by circulating brine throughout the well 10. If no DHSV 44 is required, the circulating tube 48 can be located alongside the electrical coiled tubing 20 and the control line tubing can be omitted, as shown in FIG. 13.

In another embodiment, an additional receptacle 50, located below the receptacle 14 for the wet connector 22, can be used to provide a connection for a circulating tube 52, as shown in FIG. 14. The circulating tube 52 extends down past receptacle 14 and communicates with the interior of the production casing 16 via the lower receptacle 50 to allow for circulation of the well 10 with fluid. Alternatively, the circulating tube 52 can communicate with production tubing 42 instead of casing 16. The circulating tube 52 runs alongside the electrical coiled tubing 20 and the control line tubing 46, as shown in FIG. 15, and continues below the upper receptacle 14 to connect with the lower receptacle 50, as shown in FIG. 15A. Alternatively, the control line tubing 46 can be omitted if no DHSV 44 is used. Receptacles 14 and 50 are run in together along with tubing 42. They could be installed in accordance with any of the embodiments described.

In a further embodiment, an assembly 53 can be run into a standard well 54, as shown in FIG. 16. The assembly 53 comprises an upper packer 28, the ESP 26, coiled tubing 20 housing the electrical cables 24, a receptacle 14, and a wet connector 22. In this embodiment, the receptacle 14 is connected to the production string 42 and the coiled tubing 20 housing the electrical cables 24 is attached to the exterior of the production tubing 42. The receptacle 14 can be run down to the desired depth in the standard well 54 on tubing 42. Alternatively, the wet connector 22 can be run down with the receptacle 14 instead of with assembly 53. The ESP 26 and packer 28 are lowered on a wireline and into engagement with receptacle 14.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. These embodiments are not intended to limit the scope of the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

1. An apparatus for receiving an ESP assembly, comprising: a tubing string located within a well; a tubular assembly on the lower end of the tubing string, the tubular assembly having a passage; a pocket formed on an exterior surface of the tubular assembly and projecting radially outward, the pocket having a port communicating the exterior surface with the passage of the tubular assembly; at least one tube connected at one end to the pocket, the tube fastened to the outside of the tubing string and extending to the surface; an electrical wet connector located in the tubular assembly, the wet connector having at least one conductor on its inside surface, the wet connector having an upper female end for receiving a male stab end of the ESP; and an electrical power cable run from an external power source at the surface thru the at least one tube and into electrical engagement with the conductor on the electrical wet connector, the power cable providing electrical power for the ESP.
 2. The apparatus of claim 1, wherein the tubing string, tubular assembly, and tube are cemented within the well.
 3. The apparatus of claim 1, further comprising a lower packer set in the well, the tubular assembly having a tubular seal assembly that lands within a receptacle of the lower packer.
 4. The apparatus of claim 3, further comprising a hydraulic actuated valve in the tubular assembly that allows fluid flow from below the lower packer through the tubular assembly to a pump when open and prevents fluid flow when closed, wherein a tube carrying a control line extends from the surface to the port in the pocket of the wet connector to communicate with and control the valve.
 5. The apparatus of claim 1, wherein the tubular assembly and the wet connector have bores that allow production fluid to flow through them during operation.
 6. The apparatus of claim 1, wherein the tubular assembly is attached to and protrudes downward from the tubing string as the tubing string is lowered into the well.
 7. The apparatus of claim 1, wherein the at least one tube is comprised of one of the following: a.) continuous coiled tubing; or b.) sections of tubing connected end to end.
 8. The apparatus of claim 1, wherein the tubing string has an internal diameter capable of accommodating a production casing connected to an upper portion of the tubular assembly, and the at least one tube carrying the electrical power cable.
 9. An apparatus for producing fluid from a well, comprising: a tubing string located within a well; a tubular assembly on the lower end of the tubing string, the tubular assembly having a passage; a pocket formed on an exterior surface of the tubular assembly and projecting radially outward, the pocket having a port communicating the exterior surface with the passage of the tubular assembly; at least one tube connected at one end to the pocket, the tube fastened to the outside of the tubing string and extending to the surface; an electrical wet connector located in the tubular assembly, the wet connector having at least one conductor on its inside surface, an electrical power cable run from an external power source at the surface thru the at least one tube and into electrical engagement with the conductor on the electrical wet connector; a through tubing assembly lowered into the tubing string; an electrical submersible pump and motor comprising part of the through tubing assembly, the through tubing assembly mating to the wet connector for providing electrical power to the motor via power cable; an upper packer above an intake of the pump and comprising part of the through tubing assembly for sealing a discharge of the pump from an intake of the pump; and an interior line running from the wet connector to the upper packer to energize and set the upper packer when the through tubing assembly lands at the desired location within the well.
 10. The apparatus of claim 9, wherein the tubing string, tubular assembly, and tube are cemented within the well.
 11. The apparatus of claim 9, wherein the tubular assembly is attached to and protrudes downward from the tubing string as the tubing string is lowered into the well.
 12. The apparatus of claim 9, wherein the wet connector has an upward facing receptacle and the through-tubing assembly has a downward facing stinger that stabs into the wet connector.
 13. The apparatus of claim 9, further comprising a cable that supports the through tubing assembly as the through tubing assembly is lowered into the tubing string.
 14. The apparatus of claim 9, further comprising a lower packer set in the well, the tubular assembly having a tubular seal assembly that lands within a receptacle of the lower packer.
 15. The apparatus of claim 14, further comprising a hydraulic actuated valve in the tubular assembly that allows fluid flow from below the lower packer through the tubular assembly to a pump when open and prevents fluid flow when closed, wherein a tube carrying a control line extends from the surface to the port in the pocket of the wet connector to communicate with and control the valve.
 16. The apparatus of claim 9, wherein the tubular assembly and the wet connector have bores that allow production fluid to flow through them during operation.
 17. The apparatus of claim 9, wherein a tube carrying a hydraulic control line extends from the surface to the port in the pocket of the wet connector to communicate with the internal line connected with the upper packer to energize and set the packer.
 18. A method for deploying the an electrical submersible pump system on a wireline comprising: providing a receptacle having a side pocket with a port; attaching tubing to the port and the receptacle to a string of conduit and lowering the receptacle into a well while strapping the tubing alongside the string of conduit; installing a wet mate electrical connector in the receptacle; lowering an electrical cable thru the tubing and into electrical engagement with the electrical connector; providing an electrical submersible pump with an electrical stab and lowering the electrical submersible pump on a wireline thru the conduit and into the receptacle, and electrically energizing the stab with the wet mate electrical connector.
 19. The method of claim 18, further comprising the step of pumping cement thru the receptacle and up around the conduit before installing the wet mate electrical connector in the receptacle.
 20. The method of claim 18, further comprising the steps of: flowing the cement around the receptacle and a lower portion of the tubing; and attaching a second tubing to the receptacle during the step of attaching tubing to the port on the receptacle, and circulating fluid thru second tubing and conduit before the step of installing the wet mate electrical connector in the receptacle. 